You need to register the scripts using the languagesystem keyword. Include the following at the beginning of your code.

languagesystem DFLT dflt;
languagesystem latn dflt;
languagesystem cyrl dflt;

If you have any language-specific behaviours defined you will need to add those as well, e.g.

languagesystem latn TRK; # Turkish
languagesystem cyrl SRB; # Serbian

etc.

Note that none of this has any relevance to what text or script you type in the preview pane -- it only determines which behaviours that text will exhibit as determined by your opentype features.

André

Thanks!

Er... shall I put that at the beginning of every feature script (small caps, kerning, etc)? Do I also need the script tag?
And should there be some equivalent at the end of the code?
The features actually work even now, without these, in InDesign.

Saku.

languagesystem commands should appear at the beginning of your file outside of any feature definition and before any feature definitions. You should minimally include DFLT dflt and latn dflt.

You only need to specify the script and/or language within a feature if you want that feature to behave differently depending on the script or language. Your font works fine presumably because you have not defined any language- or script-specific behaviours within it.

André